This invention relates to a device for adjusting the optical axis of a headlamp beam, particularly in a retractable headlamp assembly for use on automobiles.
Many automobiles now come equipped with retractable headlamp assemblies. The conventional retractable headlamp assembly includes a headlamp located on the front hood which is pivotally mounted so as to be projectable and retractable at will, a motor for driving the headlamp between the projected and retracted positions, and a link mechanism for coupling the headlamp to the motor so that the headlamp may be moved between these two positions.
However, due to changes in the loading of the automobile or road conditions, the optical axis of the headlamp is sometimes displaced from its correct position. Since such displacement misdirects the optical axis of the headlamp beam, the beam may momentary blind drivers in oncoming vehicles.
The conventional retractable headlamp assembly may further include an adjusting device for the optical axis of the headlamp beam (as shown in French Pat. No. 1,592,664). However,this device uses the motor for both pivoting the headlamp and for adjusting the optical axis of the headlamp beam, and in general, a high torque motor is used in order to overcome the load of the link mechanism.
Therefore the headlamp sometimes overruns its predetermined position when the optical axis of the headlamp beam is adjusted. This is because the high torque motor, whose primary purpose is to pivot the headlamps, develops too much torque to stop at the correct position since the optical axis adjusting angle is much smaller than the angle between the projected and retracted positions of the headlamp.